Patent GB-271138-A (GB)
Title: Improvements in and relating to safety guards adapted for use with power presses andthe like
IPC: F16P3/04
Filed: 1926-02-15
Abstract: 271,138. Surtees, R. Feb. 15, 1926. Interconnecting guard with starting- gear; guards, controlling.-Pendulumtype guards for power presses &c., adapted to be moved to the protective position by the press starting-pedal &c., are locked in that position by a, latch or like detent member prior to the actual engagement of the driving- clutch. The detent may be tripped during descent of the ram, and the guard may be constrained into protective position by a moving part of the machine on failure of the guard mechanism or on a " repeat." The guard arm 1, Fig. 2, is moved about its pivot 2 by a, link 12, bell-crank lever 9, and rod 6 connected with lost motion to the starting-pedal (not shown). A latch 13 on the link 12 is then engaged by a pawl 14, which is later tripped by a rod 16 on the ram 15, the guard being returned by a spring 10 when permitted by re-ascent of a roller 18 on the ram. This roller effects emergency operation of the guard, but normally just clears the side of the arm 1 in its descent. As shown in Fig. 3, the arm 1, swung about its pivot 2 against the spring 10 by pedal-actuated linkage 22 - - 26, carries a latch 27, adapted to engage by its notch 28 a lug 29 forming the pivot of a lever 30. This lever is actuated by a link 31 from the press connecting-rod to trip the latch 27 by an adjustable, abutment 35, and subsequently to bring a roller 33 against the arm 1, so that the arm is spring-returned under control of this roller, which serves also as the emergency actuator. In a modification, the roller-carrying lever is pulled down by linkage connected to the ram. Fig. 13 shows a form in which the arm 1 is normally swung by a link 66 connected to a pedal-actuated bell-crank lever 64 pivoted at a fixed point 65, and a wedge 63, actuated from the connecting-rod by a bell-crank lever and linkage (not shown), contacts with a roller on the lever 64 as soon as the latch (not shown) has been tripped, this wedge also operating the guard on a " repeat '' &c. The wedge may be replaced by a similarlyactuated rotary cam adapted to contact with a roller on the guard arm, or by a bell-crank lever 72, Fig. 16, coacting with a roller 73 on the arm 1 and actuated by linkage 61, 62 and a cam 60 on the connecting-rod. In another form, the arm 1, Fig. 18, is swung by pedal linkage 46, 47, 53 and, in emergency, by a rod 48 pulled up by a bell-crank lever 49 pivoted at 50 and actuated by a roller 52 on the connecting-rod. A latch 54, Fig. 21, is engageable by a spring-biassed pawl 55, tripped by an adjustable, rod 57 on the ram. In a further construction, the arm 1, Fig. 24, is swung into the " safe " position shown by pedal linkage 74 - - 77, a latch 78 on the bellcrank lever 75 being brought into engagement with a projection on a bracket 79 carried by the ram, descent of which finally trips the latch by bringing it into contact with an abutment 80 on the lever 75, the guard then being returned by a spring 81. Linkage (not shown) is operated by the connecting-rod in its initial movement to swing the guard arm 1 on a, " repeat " &c. The Provisional Specification describes a form in which the guard is permitted by actuation of the starting-pedal to swing into the protective position, subsequent release of the pedal being stated to trip the detaining-latch.